補體基因是造成多種疾病性別差異的原因
作者:
小柯機器人發布時間:2020/5/12 14:46:21
哈佛醫學院Steven A. McCarroll和英國倫敦國王學院Timothy J. Vyse研究組合作取得一項新成果。經過不懈努力,他們揭示補體基因在多種疾病中造成性別差異的原因。2020年5月11日,《自然》在線發表了這一成果。
研究人員發現與具有正常補體成分4(C4)基因型的個體相比,C4A和C4B的變異(其位於主要組織相容性複合體(MHC)所在位點)與精神分裂症發病風險增加相關,並且增加了7倍系統性紅斑狼瘡(SLE)發病的風險,在Sjögren症候群產生16倍的變化,在這兩種疾病中,C4A的保護作用均強於C4B。同樣的等位基因會增加精神分裂症的風險,從而大大降低SLE和Sjögren症候群的風險。
在所有三種疾病中,C4等位基因在男性中的作用要強於女性:在男性中,常見的C4A和C4B組合會使SLE產生的風險增加14倍、Sjögren’s症候群產生的風險增加31倍、精神分裂症的風險增加1.7倍(女性患病風險分別為6倍、15倍和1.26倍)。在蛋白質水平上,年齡在20至50歲之間的成年人中,男性腦脊液和血漿中C4及其效應物C3的含量均高於女性,這與相應的易感疾病年齡相對應。補體蛋白水平的性別差異可能有助於解釋C4等位基因在男性中更強的作用、女性患SLE和Sjögren症候群的風險更高以及男性更易患精神分裂症。這些結果暗示補體系統是多種易患疾病性別二態性的來源。
研究人員表示,尚不確定為什麼許多常見疾病對男人和女人的影響不同。例如,自身免疫性疾病SLE和Sjögren症候群對女性的影響是男性的9倍,而精神分裂症在男性中的發病率和嚴重性則比女性要高。這三種疾病在MHC基因座中具有最強的共同遺傳關聯。長期以來,人們一直認為SLE和Sjögren症候群是由該基因座上的人類白細胞抗原(HLA)基因等位基因引起的。
附:英文原文
Title: Complement genes contribute sex-biased vulnerability in diverse disorders
Author: Nolan Kamitaki, Aswin Sekar, Robert E. Handsaker, Heather de Rivera, Katherine Tooley, David L. Morris, Kimberly E. Taylor, Christopher W. Whelan, Philip Tombleson, Loes M. Olde Loohuis, Michael Boehnke, Robert P. Kimberly, Kenneth M. Kaufman, John B. Harley, Carl D. Langefeld, Christine E. Seidman, Michele T. Pato, Carlos N. Pato, Roel A. Ophoff, Robert R. Graham, Lindsey A. Criswell, Timothy J. Vyse, Steven A. McCarroll
Issue&Volume: 2020-05-11
Abstract: Many common illnesses, for reasons that have not been identified, differentially affect men and women. For instance, the autoimmune diseases systemic lupus erythematosus (SLE) and Sjgren’s syndrome affect nine times more women than men1, whereas schizophrenia affects men with greater frequency and severity relative to women2. All three illnesses have their strongest common genetic associations in the major histocompatibility complex (MHC) locus, an association that in SLE and Sjgren’s syndrome has long been thought to arise from alleles of the human leukocyte antigen (HLA) genes at that locus3,4,5,6. Here we show that variation of the complement component 4 (C4) genes C4A and C4B, which are also at the MHC locus and have been linked to increased risk for schizophrenia7, generates 7-fold variation in risk for SLE and 16-fold variation in risk for Sjgren’s syndrome among individuals with common C4 genotypes, with C4A protecting more strongly than C4B in both illnesses. The same alleles that increase risk for schizophrenia greatly reduce risk for SLE and Sjgren’s syndrome. In all three illnesses, C4 alleles act more strongly in men than in women: common combinations of C4A and C4B generated 14-fold variation in risk for SLE, 31-fold variation in risk for Sjgren’s syndrome, and 1.7-fold variation in schizophrenia risk among men (versus 6-fold, 15-fold and 1.26-fold variation in risk among women, respectively). At a protein level, both C4 and its effector C3 were present at higher levels in cerebrospinal fluid and plasma8,9 in men than in women among adults aged between 20 and 50 years, corresponding to the ages of differential disease vulnerability. Sex differences in complement protein levels may help to explain the more potent effects of C4 alleles in men, women’s greater risk of SLE and Sjgren’s syndrome and men’s greater vulnerability to schizophrenia. These results implicate the complement system as a source of sexual dimorphism in vulnerability to diverse illnesses.
DOI: 10.1038/s41586-020-2277-x
Source: https://www.nature.com/articles/s41586-020-2277-x